Multilayer ceramic capacitor and manufacturing method of the same

ABSTRACT

A multilayer ceramic capacitor includes: a multilayer chip in which each of dielectric layers and each of internal electrode layers are stacked, the plurality of internal electrode layers being exposed to at least one of a first end face and a second end face of the multilayer structure, the first end face being opposite to the second end face, a first external electrode provided on the first end face; a second external electrode provided on the second end face; and a fluorine compound that is adhered to at least a part of a region including a surface of the multilayer chip where neither the first external electrode nor the second external electrode is formed and surfaces of the first external electrode and the second external electrode, fluorine compound being released at a temperature of 380 degrees C. or more.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application Publication No. 2019-064669, filed onMar. 28, 2019 and Japanese Patent Application No. 2020-002420, filed onJan. 9, 2020, the entire contents of which are incorporated herein byreference.

FIELD

A certain aspect of the present invention relates to a multilayerceramic capacitor and a manufacturing method of the multilayer ceramiccapacitor.

BACKGROUND

For example, an external electrode of a ceramic electronic device suchas a multilayer ceramic capacitor has a conductive resin layer in whicha metal component and resin are mixed, in order to suppress stress whenmounting the ceramic electronic device on a substrate (for example, seeJapanese Patent Application Publication No. 2016-63008).

SUMMARY OF THE INVENTION

When the ceramic electronic device is used in high-temperature andhigh-humidity condition, the metal component of the conductive resinlayer may diffuse because of water adhered to a surface of the ceramicelectronic device. In this case, reliability of the ceramic electronicdevice may be degraded. Even if the external electrode does not have theconductive resin layer, a metal component of the external electrode maydiffuse and the reliability may be degraded.

The present invention has a purpose of providing a multilayer ceramiccapacitor and a manufacturing method of the multilayer ceramic capacitorthat are capable of improving reliability of the multilayer ceramiccapacitor.

According to an aspect of the present invention, there is provided amultilayer ceramic capacitor including: a multilayer chip in which eachof a plurality of dielectric layers and each of a plurality of internalelectrode layers are stacked, a main component of the dielectric layersbeing ceramic, the multilayer chip having a rectangular parallelepipedshape, respective of one ends of the plurality of internal electrodelayers being exposed to at least one of a first end face and a secondend face of the multilayer structure, the first end face being oppositeto the second end face, a first external electrode provided on the firstend face; a second external electrode provided on the second end face;and a fluorine compound that is adhered to at least a part of a regionincluding a surface of the multilayer chip where neither the firstexternal electrode nor the second external electrode is formed andsurfaces of the first external electrode and the second externalelectrode, the fluorine compound being released at a temperature of 380degrees C. or more.

According to another aspect of the present invention, there is provideda manufacturing method of a multilayer ceramic capacitor including:preparing a multilayer ceramic capacitor having a multilayer chip, afirst external electrode and a second external electrode, bonding afluorine compound which is released at a temperature of 380 degrees C.or more to at least a part of a region including a surface of themultilayer chip where neither the first external electrode nor thesecond external electrode is formed and surfaces of the first externalelectrode and the second external electrode, by contacting heatedfluorine rubber to the region, wherein the multilayer chip has astructure in which each of a plurality of dielectric layers and each ofa plurality of internal electrode layers are stacked, a main componentof the dielectric layers being ceramic, the multilayer structure havinga rectangular parallelepiped shape, respective one ends of the pluralityof internal electrode layers being exposed to at least one of a firstend face and a second end face of the multilayer structure, the firstend face being opposite to the second end face, wherein the firstexternal electrode is provided on the first end face, wherein the secondexternal electrode is provided on the second end face.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of a multilayer ceramic capacitorin which a cross section of a part of the multilayer ceramic capacitoris illustrated;

FIG. 2 illustrates a cross sectional view of an external electrode andis a partial cross sectional view taken along a line A-A of FIG. 1;

FIG. 3 illustrates a structure in which a fluorine compound is adheredto a multilayer ceramic capacitor;

FIG. 4 illustrates a structure in which a fluorine compound is adheredto a multilayer ceramic capacitor;

FIG. 5 illustrates a structure in which a fluorine compound is adheredto a multilayer ceramic capacitor;

FIG. 6 illustrates a manufacturing method of a multilayer ceramiccapacitor;

FIG. 7 illustrates a manufacturing method of a multilayer ceramiccapacitor;

FIG. 8 illustrates a case where a fluorine sheet is pressed to amultilayer ceramic capacitor;

FIG. 9A illustrates a GC-MS analysis of an example 1;

FIG. 9B illustrates a GC-MS analysis of an example 4; and

FIG. 10 illustrates an analysis result in which m/z is 19.

DETAILED DESCRIPTION

A description will be given of an embodiment with reference to theaccompanying drawings.

Embodiment

A description will be given of an outline of a multilayer ceramiccapacitor. FIG. 1 illustrates a perspective view of a multilayer ceramiccapacitor 100 in accordance with an embodiment, in which a cross sectionof a part of the multilayer ceramic capacitor 100 is illustrated. Asillustrated in FIG. 1, the multilayer ceramic capacitor 100 includes amultilayer chip 10 having a rectangular parallelepiped shape, and a pairof external electrodes 20 a and 20 b that are respectively provided attwo end faces of the multilayer chip 10 facing each other. In four facesother than the two end faces of the multilayer chip 10, two faces otherthan an upper face and a lower face of the multilayer chip 10 in astacking direction are referred to as side faces. The externalelectrodes 20 a and 20 b extend to the upper face, the lower face andthe two side faces of the multilayer chip 10. However, the externalelectrodes 20 a and 20 b are spaced from each other.

The multilayer chip 10 has a structure designed to have dielectriclayers 11 and internal electrode layers 12 alternately stacked. Thedielectric layer 11 includes ceramic material acting as a dielectricmaterial. The internal electrode layers 12 include a base metalmaterial. End edges of the internal electrode layers 12 are alternatelyexposed to a first end face of the multilayer chip 10 and a second endface of the multilayer chip 10 that is different from the first endface. In the embodiment, the first end face faces with the second endface. The external electrode 20 a is provided on the first end face. Theexternal electrode 20 b is provided on the second end face. Thus, theinternal electrode layers 12 are alternately conducted to the externalelectrode 20 a and the external electrode 20 b. Thus, the multilayerceramic capacitor 100 has a structure in which a plurality of dielectriclayers 11 are stacked and each two of the dielectric layers 11 sandwichthe internal electrode layer 12. In a multilayer structure of thedielectric layers 11 and the internal electrode layers 12, the internalelectrode layer 12 is positioned at an outermost layer in a stackingdirection. The upper face and the lower face of the multilayer structurethat are the internal electrode layers 12 are covered by cover layers13. A main component of the cover layer 13 is a ceramic material. Forexample, a main component of the cover layer 13 is the same as that ofthe dielectric layer 11.

For example, the multilayer ceramic capacitor 100 may have a length of0.25 mm, a width of 0.125 mm and a height of 0.125 mm. The multilayerceramic capacitor 100 may have a length of 0.4 mm, a width of 0.2 mm anda height of 0.2 mm. The multilayer ceramic capacitor 100 may have alength of 0.6 mm, a width of 0.3 mm and a height of 0.3 mm. Themultilayer ceramic capacitor 100 may have a length of 1.0 mm, a width of0.5 mm and a height of 0.5 mm. The multilayer ceramic capacitor 100 mayhave a length of 3.2 mm, a width of 1.6 mm and a height of 1.6 mm. Themultilayer ceramic capacitor 100 may have a length of 4.5 mm, a width of3.2 mm and a height of 2.5 mm. However, the size of the multilayerceramic capacitor 100 is not limited.

A main component of the internal electrode layers 12 is a base metalsuch as nickel (Ni), copper (Cu), tin (Sn) or the like. The internalelectrode layers 12 may be made of a noble metal such as platinum (Pt),palladium (Pd), silver (Ag), gold (Au) or alloy thereof. The dielectriclayers 11 are mainly composed of a ceramic material that is expressed bya general formula ABO₃ and has a perovskite structure. The perovskitestructure includes ABO_(3-α) having an off-stoichiometric composition.For example, the ceramic material is such as BaTiO₃ (barium titanate),CaZrO₃ (calcium zirconate), CaTiO₃ (calcium titanate), SrTiO₃ (strontiumtitanate), Ba_(1-x-y)Ca_(x)Sr_(y)Ti_(1-z)Zr_(z)O₃ (0≤x≤1, 0≤y≤1, 0≤z≤1)having a perovskite structure.

FIG. 2 illustrates a cross sectional view of the external electrode 20 band is a partial cross sectional view taken along a line A-A of FIG. 1.In FIG. 2, hatching for cross section is omitted. As illustrated in FIG.2, the external electrode 20 b has a structure in which a first platedlayer 22 such as Cu, a conductive resin layer 23, a second plated layer24 such as Ni and a third plated layer 25 such as Sn are formed on aground layer 21 in this order. The ground layer 21, the first platedlayer 22, the conductive resin layer 23, the second plated layer 24 andthe third plated layer 25 extend toward the two side faces, the upperface and the lower face of the multilayer chip 10 from the both endfaces of the multilayer chip 10.

A main component of the ground layer 21 is a metal such as Cu, Ni, Al(aluminum) or Zn (zinc). The ground layer 21 includes a glass componentfor densifying the ground layer 21 or a co-material for controllingsinterability of the ground layer 21. The ground layer 21 includingthese ceramic components has high adhesiveness with the cover layer 13whose main component is a ceramic material. The conductive resin layer23 is a resin layer including a metal component such as Ag. Theconductive resin layer 23 is flexible. Therefore, the conductive resinlayer 23 suppresses stress caused by deflection of a substrate on whichthe multilayer ceramic capacitor 100 is mounted. The first plated layer22 is provided in order to increase adhesiveness between the groundlayer 21 and the conductive resin layer 23. The external electrode 20 ahas the same structure as the external electrode 20 b. The conductiveresin layer 23 may not be necessarily provided.

When the external electrodes 20 a and 20 b have the structureillustrated in FIG. 2 and the multilayer ceramic capacitor 100 is usedin high-temperature and high-humidity condition, a metal component ofthe conductive resin layer 23 may diffuse because of water adhered tothe surface of the multilayer ceramic capacitor 100. In this case,reliability of the multilayer ceramic capacitor 100 may be degraded. Forexample, the metal component of the conductive resin layer 23 maydiffuse to the surface of the multilayer chip 10 between the externalelectrode 20 a and the external electrode 20 b (migration phenomena).Even if the external electrodes 20 a and 20 b do not include theconductive resin layer 23, another metal component of the externalelectrodes 20 a and 20 b may diffuse.

And so, the multilayer ceramic capacitor 100 of the embodiment has astructure in which a fluorine compound 14 is adhered to at least a partof the surface of the multilayer ceramic capacitor 100, as illustratedin FIG. 3. The fluorine compound 14 is adhered to at least a part of aregion including the surface of the multilayer chip 10 where theexternal electrode 20 a or 20 b is not formed and the surface of thesurface of the external electrodes 20 a and 20 b. For example, asillustrated in FIG. 4, the fluorine compound 14 may be adhered to only apart of the surface of the multilayer chip 10 where the externalelectrode 20 a or 20 b is not formed. Alternatively, as illustrated inFIG. 5, the fluorine compound 14 may be adhered to only a part of thesurface of the external electrodes 20 a and 20 b.

When the fluorine compound 14 is adhered to the surface of themultilayer ceramic capacitor 100, the fluorine compound 14 may directlycontact to the surface or the fluorine compound 14 and may be adhered tothe surface through another film or the like. The same thing is appliedto the following description.

In the embodiment, the fluorine compound 14 is released from the surfaceof the multilayer ceramic capacitor 100 at a temperature which is equalto or more than 380 degrees C. The fluorine compound 14 tends to be leftafter mounting the multilayer ceramic capacitor 100 with solder, becausethe fluorine compound 14 is released at a temperature which is equal toor more than 380 degrees C. The fluorine compound 14 has water-repellentcharacteristic. Therefore, even if the multilayer ceramic capacitor 100is used in high-temperature and high-humidity condition, adhesion ofwater to the surface of the multilayer ceramic capacitor 100 issuppressed. It is therefore possible to improve the reliability of themultilayer ceramic capacitor 100. The fluorine compound 14 contributesto improvement of the reliability, even if the fluorine compound 14 isadhered to the surface of the multilayer chip 10 where the externalelectrode 20 a or 20 b is not formed or the surface of the externalelectrodes 20 a and 20 b. It is preferable that the fluorine compound 14is not released from the surface of the multilayer ceramic capacitor 100at a temperature less than 380 degrees C.

The fluorine compound 14 is a compound of which a mass to charge ratiom/z is 19 in GC-MS (Gas Chromatography Mass Spectrometry) analysis. Itis preferable that there is at least one peak of released amount (alocal maximum value of the released amount) of the fluorine compound 14at a temperature of 300 degrees C. or more.

Even if the fluorine compound 14 is adhered to the surface of theexternal electrodes 20 a and 20 b, degradation of wettability of thesolder is suppressed. This is because the amount of the fluorinecompound 14 adhered to the surface of the external electrodes 20 a and20 b is small. A thickness of the fluorine compound 14 is 1 nm to 80 nm.Therefore, even if the fluorine compound 14 is adhered to the surface ofthe external electrodes 20 a and 20 b, mounting characteristic can besecured.

A region of the surface of the multilayer ceramic capacitor 100 to whichthe fluorine compound 14 is adhered is not limited. It is preferablethat the fluorine compound 14 is adhered to at least a part of a regionbetween the external electrode 20 a and the external electrode 20 b onthe upper face, the lower face and the two side faces of the multilayerchip 10.

This is because the adhesion of water to the surface of the multilayerchip 10 between the external electrode 20 a and the external electrode20 b is suppressed, and the migration is suppressed.

Alternatively, it is preferable that the fluorine compound 14 covers thewhole of the multilayer ceramic capacitor 100. This is because adhesionof water to the whole of the multilayer ceramic capacitor 100 issuppressed.

Next, a description will be given of a manufacturing method of themultilayer ceramic capacitor 100. FIG. 6 illustrates a manufacturingmethod of the multilayer ceramic capacitor 100.

(Making process of raw material powder) A dielectric material forforming the dielectric layer 11 is prepared. Generally, an A siteelement and a B site element are included in the dielectric layer 11 ina sintered phase of grains of ABO₃. For example, BaTiO₃ is tetragonalcompound having a perovskite structure and has a high dielectricconstant. Generally, BaTiO₃ is obtained by reacting a titanium materialsuch as titanium dioxide with a barium material such as barium carbonateand synthesizing barium titanate. Various methods can be used as asynthesizing method of the ceramic structuring the dielectric layer 11.For example, a solid-phase method, a sol-gel method, a hydrothermalmethod or the like can be used. The embodiment may use any of thesemethods.

An additive compound may be added to resulting ceramic powders, inaccordance with purposes. The additive compound may be an oxide of Mg(magnesium), Mn (manganese), V (vanadium), Cr (chromium) or a rare earthelement (Y (yttrium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb(terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium) andYb (ytterbium)), or an oxide of Co (cobalt), Ni, Li (lithium), B(boron), Na (sodium), K (potassium) and Si, or glass.

In the embodiment, it is preferable that ceramic particles structuringthe dielectric layer 11 are mixed with compound including additives andare calcined in a temperature range from 820 degrees C. to 1150 degreesC. Next, the resulting ceramic particles are wet-blended with additives,are dried and crushed. Thus, ceramic powder is obtained. For example, itis preferable that an average grain diameter of the resulting ceramicpowder is 50 nm to 300 nm from a viewpoint of thickness reduction of thedielectric layer 11. The grain diameter may be adjusted by crushing theresulting ceramic powder as needed. Alternatively, the grain diameter ofthe resulting ceramic power may be adjusted by combining the crushingand classifying.

(Stacking process) Next, a binder such as polyvinyl butyral (PVB) resin,an organic solvent such as ethanol or toluene, and a plasticizer areadded to the resulting dielectric material and wet-blended. With use ofthe resulting slurry, a strip-shaped dielectric green sheet with athickness of 0.8 μm or less is coated on a base material by, forexample, a die coater method or a doctor blade method, and then dried.

Next, metal conductive paste for forming an internal electrode isprovided on the surface of the dielectric green sheet by screen printingor gravure printing. The metal conductive paste includes an organicbinder. Thus, a pattern for forming an internal electrode layer isprovided. As co-materials, ceramic particles are added to the metalconductive paste. A main component of the ceramic particles is notlimited. However, it is preferable that the main component of theceramic particles is the same as that of the dielectric layer 11.

Then, the dielectric green sheets are alternately stacked while the basematerial is peeled so that the internal electrode layers 12 and thedielectric layers 11 are alternated with each other and the end edges ofthe internal electrode layers 12 are alternately exposed to both endfaces in the length direction of the dielectric layer 11 so as to bealternately led out to the pair of external electrodes 20 a and 20 b ofdifferent polarizations. For example, a total number of the stakeddielectric green sheets is 100 to 500.

After that, a cover sheet to be the cover layer 13 is cramped on themultilayer structure of the dielectric green sheets. And another coversheet to be the cover layer 13 is cramped under the multilayerstructure. Thus, a ceramic multilayer structure is obtained. After that,the binder is removed from the ceramic multilayer structure (forexample, 1.0 mm×0.5 mm) in N₂ atmosphere of 250 degrees C. to 500degrees C.

(Firing process) The resulting compact is fired for 10 minutes to 2hours in a reductive atmosphere having an oxygen partial pressure of10⁻⁷ to 10⁻¹⁰ atm in a temperature range of 1100 degrees C. to 1300degrees C.

(Re-oxidizing process) After that, a re-oxidizing process may beperformed in N₂ gas atmosphere in a temperature range of 600 degrees C.to 1000 degrees C.

(Forming process of external electrode) Metal paste including a metalfiller, a glass frit, a binder and a solvent is provided on the both endfaces of the multilayer chip 10, and is dried. After that, the metalpaste is baked. Thus, the ground layer 21 is formed. The binder and thesolvent vaporize by the baking. In the method, it is preferable that themetal filler is Cu or the like. It is preferable that the baking isperformed for 3 minutes to 30 minutes in a temperature range of 700degrees C. to 900 degrees C. It is more preferable that the baking isperformed for 5 minutes to 15 minutes in a temperature range of 760degrees C. to 840 degrees C. After that, the first plated layer 22 maybe formed on the ground layer 21 by plating.

Next, the conductive resin layer 23 is formed. For example, theconductive resin layer 23 is formed by immersion-coating thermosettingresin such as epoxy resin or phenol resin in which conductive fillerssuch as Ag, Ni, Cu or the like are kneaded, on the surface of the firstplated layer 22, and hardening the thermosetting resin by thermaltreatment. The thickness of the conductive resin layer 23 is notlimited. For example, the thickness of the conductive resin layer 23 isapproximately 10 μm to 50 μm. The thickness of the conductive resinlayer 23 may be determined in accordance with the size of a unprocessedproduct. After that, the second plated layer 24 and the third platedlayer 25 are formed on the conductive resin layer 23 by electroplatingor the like.

(Contact heating process) Next, fluorine rubber is heated to 150 degreesC. or more and is contacted to the surface of the unprocessed product.Thus, it is possible to bond the fluorine compound 14 to at least a partof the region including the region of the surface of the multilayer chip10 where the external electrode 20 a or 20 b is not provided and thesurface of the external electrodes 20 a and 20 b. In this manner, themultilayer ceramic capacitor 100 is obtained.

In the manufacturing method of the embodiment, the fluorine compound 14which is released from the surface of the multilayer ceramic capacitor100 at a temperature of 380 degrees C. or more is adhered to at least apart of the region including the region of the surface of the multilayerchip 10 where the external electrode 20 a or 20 b is not formed and thesurface of the surface of the external electrodes 20 a and 20 b, byheating the fluorine rubber to 150 degrees C. or more and contacting thefluorine rubber to the surface of the multilayer ceramic capacitor 100.Therefore, the fluorine compound 14 tends to be left after mounting themultilayer ceramic capacitor 100 with solder. The fluorine compound 14has water-repellent characteristic. Therefore, even if the multilayerceramic capacitor 100 is used in high-temperature and high-humiditycondition, adhesion of water to the surface of the multilayer ceramiccapacitor 100 is suppressed. It is therefore possible to improve thereliability of the multilayer ceramic capacitor 100.

The ground layer 21 may be fired together with the multilayer chip 10.In this case, as illustrated in FIG. 7, the binder is removed from theceramic multilayer structure in N₂ atmosphere of 250 degrees C. to 500degrees C. After that, metal paste including a metal filler, aco-material, a binder and a solvent is provided on the both end faces ofthe ceramic multilayer structure by a dipping method or the like and isdried. After that, the metal paste is fired together with the ceramicmultilayer structure. Firing condition is described in theabove-mentioned firing process. After that, a re-oxidizing process maybe performed in N₂ gas atmosphere in a temperature range of 600 degreesC. to 1000 degrees C. After that, the first plated layer 22 is formed onthe ground layer 21 by plating. Next, the conductive resin layer 23 isformed on the first plated layer 22. After that, the second plated layer24 and the third plated layer 25 are formed on the conductive resinlayer 23 by electroplating or the like.

As illustrated in FIG. 8, the multilayer ceramic capacitors 100 may bemounted on a substrate 16 before bonding the fluorine compound 14 to themultilayer ceramic capacitors 100. A sheet 17 of the fluorine rubber maybe heated and may be pressed to the multilayer ceramic capacitors 100.Thereby, the fluorine compound 14 may be adhered to at least a part ofthe region including the region of the surface of the multilayer chip 10where the external electrode 20 a or 20 b is not provided and thesurface of the external electrodes 20 a and 20 b. In this case, thefluorine compound 14 is adhered to the substrate 16. It is thereforepossible to suppress breakdown caused by condensation on the surface ofthe substrate 16. It is possible to suppress defect of mounting, becausethe multilayer ceramic capacitors 100 are mounted before pressing thesheet 17 of the fluorine rubber to the multilayer ceramic capacitors100. It is preferable that an apparent density of the sheet 17 of thefluorine rubber is 0.75 g/cm³ or less. This is because, when theapparent density of the fluorine rubber is large, the sheet 17 ishardened. And, when the apparent density of the fluorine rubber is largeand the sheet 17 is pressed to the multilayer ceramic capacitor 100, itis not possible to sufficiently cover the chips with the sheet 17. And,when the sheet 17 having a large apparent density is pressed so as tocover the chips, excessive force is applied to the chips and the chipsmay be damaged. The apparent density is mass of the sheet 17 withrespect to the volume of the sheet 17.

In the embodiments, the multilayer ceramic capacitor is described as anexample of ceramic electronic devices. However, the embodiments are notlimited to the multilayer ceramic capacitor. For example, theembodiments may be applied to another electronic device such as varistoror thermistor.

Examples

The multilayer ceramic capacitors in accordance with the embodiment weremade and the property was measured.

Examples 1 to 4

An organic binder was kneaded with ceramic powder, of which a maincomponent was barium titanate, having reduction resistant. Thus, slurrywas prepared. The slurry was formed into a sheet by doctor blade. Thus,a dielectric green sheet was made. Metal conductive paste of Ni having apredetermined pattern was provided on the dielectric green sheet byscreen printing. Thus, an internal electrode pattern was formed. Thedielectric green sheet on which the internal electrode pattern wasformed was stamped into a predetermined size. And a predetermined numberof the dielectric green sheets were stacked. And a ceramic multilayerstructure was made by thermos-compression.

Next, the ceramic multilayer structure was cut into predetermined chipsizes and was divided. Metal paste including a co-material was providedon the both end faces of the ceramic multilayer structure (faces exposedto external electrodes) by an immersion method so that the metal pastehas a predetermined electrode width (E size).

Next, the resulting ceramic multilayer structure was fired at a 1250degrees C. in nitrogen or hydrogen atmosphere and was subjected to apredetermined thermal treatment. Thus, the ground layer 21 covering themultilayer chip 10 and the both end faces of the multilayer chip 10.Next, the surface of the ground layer 21 was subjected to dry polishingwith use of “whitemorundum” (registered trademark) as a polishing agent.After that, the first plated layer 22 was formed by Cu-plating. Next,conductive resin paste of which viscosity was adjusted to apredetermined value (10 to 30 Pa·s) was provided on the surface of thefirst plated layer 22 by an immersion method. Epoxy resin in which an Agfiller was kneaded was used as the conductive resin paste. After that,the conductive resin layer 23 was formed by hardening the conductiveresin paste by a thermal treatment. And, the second plated layer 24 andthe third plated layer 25 were formed on the conductive resin layer 23by Ni-plating and Sn-plating. The resulting multilayer ceramic capacitor100 had a length of 3.2 mm, a width of 2.5 mm and a height of 2.5 mm.

Fluorine rubber was heated together with the multilayer ceramiccapacitor 100. And the fluorine rubber was contacted to the surface ofthe multilayer ceramic capacitor 100. Thus, the fluorine compound 14 wasadhered to the surface of the multilayer ceramic capacitor 100. In theexample 1, the heating temperature of the fluorine rubber was 150degrees C. In the example 2, the heating temperature of the fluorinerubber was 170 degrees C. In the example 3, the heating temperature ofthe fluorine rubber was 190 degrees C. In the example 4, the heatingtemperature of the fluorine rubber was 210 degrees C.

In the comparative example, the fluorine compound 14 was not adhered(without water-repellent process).

With respect to the multilayer ceramic capacitors 100 of the examples 1and 2, it was confirmed whether the fluorine compound was released. Themultilayer ceramic capacitors 100 were heated from 60 degrees C. to 600degrees C., and the component of the gas and the released amount fromthe mass of the released gas were analyzed, by gas chromatograph massspectrometry: GC-MS (Gas Chromatography Mass Spectrometry) (EGA/Py-3030Dmade by Frontier Laboratories/GC7980A made by Agilent/JMS1050GC made byJEOL).

Analysis condition was as follows.

Thermal Decomposition Condition:

Thermal decomposition temperature was 60 degrees C. to 800 degrees C.Temperature rising rate was 20 degrees C./min.

Column:

Column inner diameter was 0.25 mm.Column length was 5 m.

Oven Temperature Condition:

Temperature range was 250 degrees C.Holding time was 37 minutes.

FIG. 9A illustrates a GC-MS analysis result of the example 1. FIG. 9Billustrates a GC-MS analysis result of the example 4. In FIG. 9A andFIG. 9B, a horizontal axis indicates the mass to charge ratio (m/zvalue). A vertical axis indicates peak intensity. FIG. 9A and FIG. 9Billustrate results at a time when a heated temperature was 450 degreesC. As illustrated in FIG. 9A and FIG. 9B, releasing of fluorine of whichM/z was 19 was confirmed at the time when the heated temperature was 450degrees C.

FIG. 10 focuses on m/z=19 in the GC-MS analysis results of the examples1 and 4. A horizontal axis of FIG. 10 indicates a temperature. Asillustrated in FIG. 10, in the examples 1 and 4, the releasing of thefluorine compound was not observed at a temperature less than 380degrees C., and the releasing of the fluorine compound was observed at ahigh temperature of 380 degrees C. or more. It is thought that this wasbecause the releasing of the fluorine compound was suppressed at a lowtemperature, because contact heating of the fluorine rubber wasperformed. In the results of FIG. 10, a peak of the released amount ofthe fluorine compound was observed at a temperature of 380 degrees C. ormore.

Next, other 400 samples were subjected to a humidity resistance test,with respect to each of the examples 1 to 4 and the comparative example.In the humidity resistance test, each sample was left under a conditionat a temperature of 120 degrees C. and at a relative humidity of 85%.And, a voltage of 1.5 times as much as a rated voltage was applied toeach sample for 100 hours. And an electrical value (insulatingresistance between electrodes) was measured. When the insulatingresistance×a capacity was 100 MΩ·μF or more, it was determined asacceptance. When the insulating resistance×the capacity was less than100 MΩ·μF, it was determined as non-acceptance. A ratio of samplesdetermined as non-acceptance was measured with respect to 400 samples.

Next, other 400 samples were subjected to a condensation test, withrespect to each of the examples 1 to 4 and the comparative example. Thesamples were mounted on reliable substrates (CEM 3). The samples wereput in a thermo-hygrostat tank. And, 16 V was applied to the samples. Acondensation test program of JIS 60068-2-30 was performed 6 times. Afterthat, it was confirmed whether the migration occurred or not. Thecondition of each cycle of the program is as follows. (1) The humiditywas kept at 98%. The temperature was changed from 25 degrees C. to 55degrees C. for 3 hours. (2) The temperature was kept at 55 degrees C.The humidity was changed from 98% to 93% for 15 minutes. (3) Thetemperature was kept at 55 degrees C. and the humidity was kept at 93%for 9 hours and 25 minutes. (4) The humidity was kept at 93%. Thetemperature was changed from 55 degrees C. to 25 degrees C. for threehours. (5) The temperature was kept at 25 degrees C. and the humiditywas kept at 93% for 3 hours. (6) The temperature was kept at 25 degreesC. The humidity was changed from 93% to 98% for 5 hours and 30 minutes.Each sample was observed by a stereomicroscope of 40 magnifications. Andit was determined whether there was a precipitate between externalelectrodes. When there was a precipitate, it was determined that themigration occurred. A ratio of samples in which the migration occurredwas measured with respect to 400 samples.

Table 1 shows the results of the humidity resistance test and thecondensation test. As shown in Table 1, in the comparative example, thenon-acceptance rate of the humidity resistance test was high. On theother hand, in the examples 1 to 4, the non-acceptance rate of thehumidity resistance test was low. It is thought that this was becausethe water-repellent characteristic was achieved because the fluorinecompound 14 was formed.

TABLE 1 COMPAR- EX- EX- EX- EX- ATIVE AMPLE AMPLE AMPLE AMPLE EXAMPLE 12 3 4 HUMIDITY  7/400 0/400 0/400 0/400 0/400 RESISTANCE TEST CONDEN-23/400 0/400 0/400 0/400 0/400 SATION TEST

Next, non-acceptance rate of the condensation test of the comparativeexample was high. On the other hand, the non-acceptance rate of thecondensation test was low in the examples 1 to 4. It is thought thatthis was because the water-repellent characteristic was achieved becausethe fluorine compound 14 was formed.

Although the embodiments of the present invention have been described indetail, it is to be understood that the various change, substitutions,and alterations could be made hereto without departing from the spiritand scope of the invention.

What is claimed is:
 1. A multilayer ceramic capacitor comprising: amultilayer chip in which each of a plurality of dielectric layers andeach of a plurality of internal electrode layers are stacked, a maincomponent of the dielectric layers being ceramic, the multilayer chiphaving a rectangular parallelepiped shape, respective one ends of theplurality of internal electrode layers being exposed to at least one ofa first end face and a second end face of the multilayer structure, thefirst end face being opposite to the second end face, a first externalelectrode provided on the first end face; a second external electrodeprovided on the second end face; and a fluorine compound that is adheredto at least a part of a region including a surface of the multilayerchip where neither the first external electrode nor the second externalelectrode is formed and surfaces of the first external electrode and thesecond external electrode, the fluorine compound being released at atemperature of 380 degrees C. or more.
 2. The multilayer ceramiccapacitor as claimed in claim 1, wherein the fluorine compound is acompound of which a mass to charge ratio “m/z” is 19 in a GC-MSanalysis.
 3. The multilayer ceramic capacitor as claimed in claim 1,wherein there is a peak of a released amount of the fluorine compound,at a temperature of 380 degrees C. or more.
 4. The multilayer ceramiccapacitor as claimed in claim 1, wherein the fluorine compound isadhered to the surface of the multilayer chip between the first externalelectrode and the second external electrode.
 5. The multilayer ceramiccapacitor as claimed in claim 1, wherein the first external electrodeand the second external electrode include a conductive resin layerincluding a metal component.
 6. The multilayer ceramic capacitor asclaimed in claim 1, wherein the fluorine compound is not released at atemperature less than 380 degrees C.
 7. A manufacturing method of amultilayer ceramic capacitor comprising: preparing a multilayer ceramiccapacitor having a multilayer chip, a first external electrode and asecond external electrode, bonding a fluorine compound which is releasedat a temperature of 380 degrees C. or more to at least a part of aregion including a surface of the multilayer chip where neither thefirst external electrode nor the second external electrode is formed andsurfaces of the first external electrode and the second externalelectrode, by contacting heated fluorine rubber to the region, whereinthe multilayer chip has a structure in which each of a plurality ofdielectric layers and each of a plurality of internal electrode layersare stacked, a main component of the dielectric layers being ceramic,the multilayer structure having a rectangular parallelepiped shape,respective one ends of the plurality of internal electrode layers beingexposed to at least one of a first end face and a second end face of themultilayer structure, the first end face being opposite to the secondend face, wherein the first external electrode is provided on the firstend face, wherein the second external electrode is provided on thesecond end face.
 8. The method as claimed in claim 7, wherein thefluorine compound is adhered to at least the part of the regionincluding the surface of the multilayer chip where neither the firstexternal electrode nor the second external electrode is formed and thesurfaces of the first external electrode and the second externalelectrode, by mounting the multilayer ceramic capacitor on a substratebefore the fluorine compound is adhered and contacting the heatedfluorine rubber to the multilayer ceramic capacitor.
 9. The method asclaimed in claim 7, wherein the fluorine rubber that is heated to 150degrees C. or more is contacted to the region including the surface ofthe multilayer chip where neither the first external electrode nor thesecond external electrode is formed and the surfaces of the firstexternal electrode and the second external electrode.